Merge branch 'akpm'

[linux-2.6/next.git] / drivers / acpi / acpica / evxface.c

/******************************************************************************
 *
 * Module Name: evxface - External interfaces for ACPI events
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2011, Intel Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include "accommon.h"
#include "acnamesp.h"
#include "acevents.h"
#include "acinterp.h"

#define _COMPONENT          ACPI_EVENTS
ACPI_MODULE_NAME("evxface")

/*******************************************************************************
 *
 * FUNCTION:    acpi_install_exception_handler
 *
 * PARAMETERS:  Handler         - Pointer to the handler function for the
 *                                event
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Saves the pointer to the handler function
 *
 ******************************************************************************/
#ifdef ACPI_FUTURE_USAGE
acpi_status acpi_install_exception_handler(acpi_exception_handler handler)
{
        acpi_status status;

        ACPI_FUNCTION_TRACE(acpi_install_exception_handler);

        status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /* Don't allow two handlers. */

        if (acpi_gbl_exception_handler) {
                status = AE_ALREADY_EXISTS;
                goto cleanup;
        }

        /* Install the handler */

        acpi_gbl_exception_handler = handler;

      cleanup:
        (void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
        return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_install_exception_handler)
#endif                          /*  ACPI_FUTURE_USAGE  */

/*******************************************************************************
 *
 * FUNCTION:    acpi_install_global_event_handler
 *
 * PARAMETERS:  Handler         - Pointer to the global event handler function
 *              Context         - Value passed to the handler on each event
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Saves the pointer to the handler function. The global handler
 *              is invoked upon each incoming GPE and Fixed Event. It is
 *              invoked at interrupt level at the time of the event dispatch.
 *              Can be used to update event counters, etc.
 *
 ******************************************************************************/
acpi_status
acpi_install_global_event_handler(ACPI_GBL_EVENT_HANDLER handler, void *context)
{
        acpi_status status;

        ACPI_FUNCTION_TRACE(acpi_install_global_event_handler);

        /* Parameter validation */

        if (!handler) {
                return_ACPI_STATUS(AE_BAD_PARAMETER);
        }

        status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /* Don't allow two handlers. */

        if (acpi_gbl_global_event_handler) {
                status = AE_ALREADY_EXISTS;
                goto cleanup;
        }

        acpi_gbl_global_event_handler = handler;
        acpi_gbl_global_event_handler_context = context;

      cleanup:
        (void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
        return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_install_global_event_handler)

/*******************************************************************************
 *
 * FUNCTION:    acpi_install_fixed_event_handler
 *
 * PARAMETERS:  Event           - Event type to enable.
 *              Handler         - Pointer to the handler function for the
 *                                event
 *              Context         - Value passed to the handler on each GPE
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Saves the pointer to the handler function and then enables the
 *              event.
 *
 ******************************************************************************/
acpi_status
acpi_install_fixed_event_handler(u32 event,
                                 acpi_event_handler handler, void *context)
{
        acpi_status status;

        ACPI_FUNCTION_TRACE(acpi_install_fixed_event_handler);

        /* Parameter validation */

        if (event > ACPI_EVENT_MAX) {
                return_ACPI_STATUS(AE_BAD_PARAMETER);
        }

        status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /* Don't allow two handlers. */

        if (NULL != acpi_gbl_fixed_event_handlers[event].handler) {
                status = AE_ALREADY_EXISTS;
                goto cleanup;
        }

        /* Install the handler before enabling the event */

        acpi_gbl_fixed_event_handlers[event].handler = handler;
        acpi_gbl_fixed_event_handlers[event].context = context;

        status = acpi_clear_event(event);
        if (ACPI_SUCCESS(status))
                status = acpi_enable_event(event, 0);
        if (ACPI_FAILURE(status)) {
                ACPI_WARNING((AE_INFO, "Could not enable fixed event 0x%X",
                              event));

                /* Remove the handler */

                acpi_gbl_fixed_event_handlers[event].handler = NULL;
                acpi_gbl_fixed_event_handlers[event].context = NULL;
        } else {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Enabled fixed event %X, Handler=%p\n", event,
                                  handler));
        }

      cleanup:
        (void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
        return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_install_fixed_event_handler)

/*******************************************************************************
 *
 * FUNCTION:    acpi_remove_fixed_event_handler
 *
 * PARAMETERS:  Event           - Event type to disable.
 *              Handler         - Address of the handler
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Disables the event and unregisters the event handler.
 *
 ******************************************************************************/
acpi_status
acpi_remove_fixed_event_handler(u32 event, acpi_event_handler handler)
{
        acpi_status status = AE_OK;

        ACPI_FUNCTION_TRACE(acpi_remove_fixed_event_handler);

        /* Parameter validation */

        if (event > ACPI_EVENT_MAX) {
                return_ACPI_STATUS(AE_BAD_PARAMETER);
        }

        status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /* Disable the event before removing the handler */

        status = acpi_disable_event(event, 0);

        /* Always Remove the handler */

        acpi_gbl_fixed_event_handlers[event].handler = NULL;
        acpi_gbl_fixed_event_handlers[event].context = NULL;

        if (ACPI_FAILURE(status)) {
                ACPI_WARNING((AE_INFO,
                              "Could not write to fixed event enable register 0x%X",
                              event));
        } else {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Disabled fixed event %X\n",
                                  event));
        }

        (void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
        return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_remove_fixed_event_handler)

/*******************************************************************************
 *
 * FUNCTION:    acpi_populate_handler_object
 *
 * PARAMETERS:  handler_obj        - Handler object to populate
 *              handler_type       - The type of handler:
 *                                  ACPI_SYSTEM_NOTIFY: system_handler (00-7f)
 *                                  ACPI_DEVICE_NOTIFY: driver_handler (80-ff)
 *                                  ACPI_ALL_NOTIFY:  both system and device
 *              handler            - Address of the handler
 *              context            - Value passed to the handler on each GPE
 *              next               - Address of a handler object to link to
 *
 * RETURN:      None
 *
 * DESCRIPTION: Populate a handler object.
 *
 ******************************************************************************/
static void
acpi_populate_handler_object(struct acpi_object_notify_handler *handler_obj,
                             u32 handler_type,
                             acpi_notify_handler handler, void *context,
                             struct acpi_object_notify_handler *next)
{
        handler_obj->handler_type = handler_type;
        handler_obj->handler = handler;
        handler_obj->context = context;
        handler_obj->next = next;
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_add_handler_object
 *
 * PARAMETERS:  parent_obj         - Parent of the new object
 *              handler            - Address of the handler
 *              context            - Value passed to the handler on each GPE
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create a new handler object and populate it.
 *
 ******************************************************************************/
static acpi_status
acpi_add_handler_object(struct acpi_object_notify_handler *parent_obj,
                        acpi_notify_handler handler, void *context)
{
        struct acpi_object_notify_handler *handler_obj;

        /* The parent must not be a defice notify handler object. */
        if (parent_obj->handler_type & ACPI_DEVICE_NOTIFY)
                return AE_BAD_PARAMETER;

        handler_obj = ACPI_ALLOCATE_ZEROED(sizeof(*handler_obj));
        if (!handler_obj)
                return AE_NO_MEMORY;

        acpi_populate_handler_object(handler_obj,
                                        ACPI_SYSTEM_NOTIFY,
                                        handler, context,
                                        parent_obj->next);
        parent_obj->next = handler_obj;

        return AE_OK;
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_install_notify_handler
 *
 * PARAMETERS:  Device          - The device for which notifies will be handled
 *              handler_type    - The type of handler:
 *                                  ACPI_SYSTEM_NOTIFY: system_handler (00-7f)
 *                                  ACPI_DEVICE_NOTIFY: driver_handler (80-ff)
 *                                  ACPI_ALL_NOTIFY:  both system and device
 *              Handler         - Address of the handler
 *              Context         - Value passed to the handler on each GPE
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Install a handler for notifies on an ACPI device
 *
 ******************************************************************************/
acpi_status
acpi_install_notify_handler(acpi_handle device,
                            u32 handler_type,
                            acpi_notify_handler handler, void *context)
{
        union acpi_operand_object *obj_desc;
        union acpi_operand_object *notify_obj;
        struct acpi_namespace_node *node;
        acpi_status status;

        ACPI_FUNCTION_TRACE(acpi_install_notify_handler);

        /* Parameter validation */

        if ((!device) ||
            (!handler) || (handler_type > ACPI_MAX_NOTIFY_HANDLER_TYPE)) {
                return_ACPI_STATUS(AE_BAD_PARAMETER);
        }

        status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /* Convert and validate the device handle */

        node = acpi_ns_validate_handle(device);
        if (!node) {
                status = AE_BAD_PARAMETER;
                goto unlock_and_exit;
        }

        /*
         * Root Object:
         * Registering a notify handler on the root object indicates that the
         * caller wishes to receive notifications for all objects. Note that
         * only one <external> global handler can be regsitered (per notify type).
         */
        if (device == ACPI_ROOT_OBJECT) {

                /* Make sure the handler is not already installed */

                if (((handler_type & ACPI_SYSTEM_NOTIFY) &&
                     acpi_gbl_system_notify.handler) ||
                    ((handler_type & ACPI_DEVICE_NOTIFY) &&
                     acpi_gbl_device_notify.handler)) {
                        status = AE_ALREADY_EXISTS;
                        goto unlock_and_exit;
                }

                if (handler_type & ACPI_SYSTEM_NOTIFY) {
                        acpi_gbl_system_notify.node = node;
                        acpi_gbl_system_notify.handler = handler;
                        acpi_gbl_system_notify.context = context;
                }

                if (handler_type & ACPI_DEVICE_NOTIFY) {
                        acpi_gbl_device_notify.node = node;
                        acpi_gbl_device_notify.handler = handler;
                        acpi_gbl_device_notify.context = context;
                }

                /* Global notify handler installed */
        }

        /*
         * All Other Objects:
         * Caller will only receive notifications specific to the target object.
         * Note that only certain object types can receive notifications.
         */
        else {
                /* Notifies allowed on this object? */

                if (!acpi_ev_is_notify_object(node)) {
                        status = AE_TYPE;
                        goto unlock_and_exit;
                }

                /* Check for an existing internal object */

                obj_desc = acpi_ns_get_attached_object(node);
                if (obj_desc) {

                        /* Object exists. */

                        /* For a device notify, make sure there's no handler. */
                        if ((handler_type & ACPI_DEVICE_NOTIFY) &&
                             obj_desc->common_notify.device_notify) {
                                status = AE_ALREADY_EXISTS;
                                goto unlock_and_exit;
                        }

                        /* System notifies may have more handlers installed. */
                        notify_obj = obj_desc->common_notify.system_notify;

                        if ((handler_type & ACPI_SYSTEM_NOTIFY) && notify_obj) {
                                struct acpi_object_notify_handler *parent_obj;

                                if (handler_type & ACPI_DEVICE_NOTIFY) {
                                        status = AE_ALREADY_EXISTS;
                                        goto unlock_and_exit;
                                }

                                parent_obj = &notify_obj->notify;
                                status = acpi_add_handler_object(parent_obj,
                                                                 handler,
                                                                 context);
                                goto unlock_and_exit;
                        }
                } else {
                        /* Create a new object */

                        obj_desc = acpi_ut_create_internal_object(node->type);
                        if (!obj_desc) {
                                status = AE_NO_MEMORY;
                                goto unlock_and_exit;
                        }

                        /* Attach new object to the Node */

                        status =
                            acpi_ns_attach_object(device, obj_desc, node->type);

                        /* Remove local reference to the object */

                        acpi_ut_remove_reference(obj_desc);
                        if (ACPI_FAILURE(status)) {
                                goto unlock_and_exit;
                        }
                }

                /* Install the handler */

                notify_obj =
                    acpi_ut_create_internal_object(ACPI_TYPE_LOCAL_NOTIFY);
                if (!notify_obj) {
                        status = AE_NO_MEMORY;
                        goto unlock_and_exit;
                }

                acpi_populate_handler_object(&notify_obj->notify,
                                                handler_type,
                                                handler, context,
                                                NULL);

                if (handler_type & ACPI_SYSTEM_NOTIFY) {
                        obj_desc->common_notify.system_notify = notify_obj;
                }

                if (handler_type & ACPI_DEVICE_NOTIFY) {
                        obj_desc->common_notify.device_notify = notify_obj;
                }

                if (handler_type == ACPI_ALL_NOTIFY) {

                        /* Extra ref if installed in both */

                        acpi_ut_add_reference(notify_obj);
                }
        }

      unlock_and_exit:
        (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
        return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_install_notify_handler)

/*******************************************************************************
 *
 * FUNCTION:    acpi_remove_notify_handler
 *
 * PARAMETERS:  Device          - The device for which notifies will be handled
 *              handler_type    - The type of handler:
 *                                  ACPI_SYSTEM_NOTIFY: system_handler (00-7f)
 *                                  ACPI_DEVICE_NOTIFY: driver_handler (80-ff)
 *                                  ACPI_ALL_NOTIFY:  both system and device
 *              Handler         - Address of the handler
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Remove a handler for notifies on an ACPI device
 *
 ******************************************************************************/
acpi_status
acpi_remove_notify_handler(acpi_handle device,
                           u32 handler_type, acpi_notify_handler handler)
{
        union acpi_operand_object *notify_obj;
        union acpi_operand_object *obj_desc;
        struct acpi_namespace_node *node;
        acpi_status status;

        ACPI_FUNCTION_TRACE(acpi_remove_notify_handler);

        /* Parameter validation */

        if ((!device) ||
            (!handler) || (handler_type > ACPI_MAX_NOTIFY_HANDLER_TYPE)) {
                status = AE_BAD_PARAMETER;
                goto exit;
        }


        /* Make sure all deferred tasks are completed */
        acpi_os_wait_events_complete(NULL);

        status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
        if (ACPI_FAILURE(status)) {
                goto exit;
        }

        /* Convert and validate the device handle */

        node = acpi_ns_validate_handle(device);
        if (!node) {
                status = AE_BAD_PARAMETER;
                goto unlock_and_exit;
        }

        /* Root Object */

        if (device == ACPI_ROOT_OBJECT) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Removing notify handler for namespace root object\n"));

                if (((handler_type & ACPI_SYSTEM_NOTIFY) &&
                     !acpi_gbl_system_notify.handler) ||
                    ((handler_type & ACPI_DEVICE_NOTIFY) &&
                     !acpi_gbl_device_notify.handler)) {
                        status = AE_NOT_EXIST;
                        goto unlock_and_exit;
                }

                if (handler_type & ACPI_SYSTEM_NOTIFY) {
                        acpi_gbl_system_notify.node = NULL;
                        acpi_gbl_system_notify.handler = NULL;
                        acpi_gbl_system_notify.context = NULL;
                }

                if (handler_type & ACPI_DEVICE_NOTIFY) {
                        acpi_gbl_device_notify.node = NULL;
                        acpi_gbl_device_notify.handler = NULL;
                        acpi_gbl_device_notify.context = NULL;
                }
        }

        /* All Other Objects */

        else {
                /* Notifies allowed on this object? */

                if (!acpi_ev_is_notify_object(node)) {
                        status = AE_TYPE;
                        goto unlock_and_exit;
                }

                /* Check for an existing internal object */

                obj_desc = acpi_ns_get_attached_object(node);
                if (!obj_desc) {
                        status = AE_NOT_EXIST;
                        goto unlock_and_exit;
                }

                /* Object exists - make sure there's an existing handler */

                if (handler_type & ACPI_SYSTEM_NOTIFY) {
                        struct acpi_object_notify_handler *handler_obj;
                        struct acpi_object_notify_handler *parent_obj;

                        notify_obj = obj_desc->common_notify.system_notify;
                        if (!notify_obj) {
                                status = AE_NOT_EXIST;
                                goto unlock_and_exit;
                        }

                        handler_obj = &notify_obj->notify;
                        parent_obj = NULL;
                        while (handler_obj->handler != handler) {
                                if (handler_obj->next) {
                                        parent_obj = handler_obj;
                                        handler_obj = handler_obj->next;
                                } else {
                                        break;
                                }
                        }

                        if (handler_obj->handler != handler) {
                                status = AE_BAD_PARAMETER;
                                goto unlock_and_exit;
                        }

                        /*
                         * Remove the handler.  There are three possible cases.
                         * First, we may need to remove a non-embedded object.
                         * Second, we may need to remove the embedded object's
                         * handler data, while non-embedded objects exist.
                         * Finally, we may need to remove the embedded object
                         * entirely along with its container.
                         */
                        if (parent_obj) {
                                /* Non-embedded object is being removed. */
                                parent_obj->next = handler_obj->next;
                                ACPI_FREE(handler_obj);
                        } else if (notify_obj->notify.next) {
                                /*
                                 * The handler matches the embedded object, but
                                 * there are more handler objects in the list.
                                 * Replace the embedded object's data with the
                                 * first next object's data and remove that
                                 * object.
                                 */
                                parent_obj = &notify_obj->notify;
                                handler_obj = notify_obj->notify.next;
                                *parent_obj = *handler_obj;
                                ACPI_FREE(handler_obj);
                        } else {
                                /* No more handler objects in the list. */
                                obj_desc->common_notify.system_notify = NULL;
                                acpi_ut_remove_reference(notify_obj);
                        }
                }

                if (handler_type & ACPI_DEVICE_NOTIFY) {
                        notify_obj = obj_desc->common_notify.device_notify;
                        if (!notify_obj) {
                                status = AE_NOT_EXIST;
                                goto unlock_and_exit;
                        }

                        if (notify_obj->notify.handler != handler) {
                                status = AE_BAD_PARAMETER;
                                goto unlock_and_exit;
                        }

                        /* Remove the handler */
                        obj_desc->common_notify.device_notify = NULL;
                        acpi_ut_remove_reference(notify_obj);
                }
        }

      unlock_and_exit:
        (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
      exit:
        if (ACPI_FAILURE(status))
                ACPI_EXCEPTION((AE_INFO, status, "Removing notify handler"));
        return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_remove_notify_handler)

/*******************************************************************************
 *
 * FUNCTION:    acpi_install_gpe_handler
 *
 * PARAMETERS:  gpe_device      - Namespace node for the GPE (NULL for FADT
 *                                defined GPEs)
 *              gpe_number      - The GPE number within the GPE block
 *              Type            - Whether this GPE should be treated as an
 *                                edge- or level-triggered interrupt.
 *              Address         - Address of the handler
 *              Context         - Value passed to the handler on each GPE
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Install a handler for a General Purpose Event.
 *
 ******************************************************************************/
acpi_status
acpi_install_gpe_handler(acpi_handle gpe_device,
                         u32 gpe_number,
                         u32 type, acpi_gpe_handler address, void *context)
{
        struct acpi_gpe_event_info *gpe_event_info;
        struct acpi_gpe_handler_info *handler;
        acpi_status status;
        acpi_cpu_flags flags;

        ACPI_FUNCTION_TRACE(acpi_install_gpe_handler);

        /* Parameter validation */

        if ((!address) || (type & ~ACPI_GPE_XRUPT_TYPE_MASK)) {
                return_ACPI_STATUS(AE_BAD_PARAMETER);
        }

        status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /* Allocate memory for the handler object */

        handler = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_gpe_handler_info));
        if (!handler) {
                status = AE_NO_MEMORY;
                goto unlock_and_exit;
        }

        flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);

        /* Ensure that we have a valid GPE number */

        gpe_event_info = acpi_ev_get_gpe_event_info(gpe_device, gpe_number);
        if (!gpe_event_info) {
                status = AE_BAD_PARAMETER;
                goto free_and_exit;
        }

        /* Make sure that there isn't a handler there already */

        if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
            ACPI_GPE_DISPATCH_HANDLER) {
                status = AE_ALREADY_EXISTS;
                goto free_and_exit;
        }

        /* Allocate and init handler object */

        handler->address = address;
        handler->context = context;
        handler->method_node = gpe_event_info->dispatch.method_node;
        handler->original_flags = gpe_event_info->flags &
                        (ACPI_GPE_XRUPT_TYPE_MASK | ACPI_GPE_DISPATCH_MASK);

        /*
         * If the GPE is associated with a method, it might have been enabled
         * automatically during initialization, in which case it has to be
         * disabled now to avoid spurious execution of the handler.
         */

        if ((handler->original_flags & ACPI_GPE_DISPATCH_METHOD)
            && gpe_event_info->runtime_count) {
                handler->originally_enabled = 1;
                (void)acpi_ev_remove_gpe_reference(gpe_event_info);
        }

        /* Install the handler */

        gpe_event_info->dispatch.handler = handler;

        /* Setup up dispatch flags to indicate handler (vs. method) */

        gpe_event_info->flags &=
            ~(ACPI_GPE_XRUPT_TYPE_MASK | ACPI_GPE_DISPATCH_MASK);
        gpe_event_info->flags |= (u8) (type | ACPI_GPE_DISPATCH_HANDLER);

        acpi_os_release_lock(acpi_gbl_gpe_lock, flags);

unlock_and_exit:
        (void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
        return_ACPI_STATUS(status);

free_and_exit:
        acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
        ACPI_FREE(handler);
        goto unlock_and_exit;
}

ACPI_EXPORT_SYMBOL(acpi_install_gpe_handler)

/*******************************************************************************
 *
 * FUNCTION:    acpi_remove_gpe_handler
 *
 * PARAMETERS:  gpe_device      - Namespace node for the GPE (NULL for FADT
 *                                defined GPEs)
 *              gpe_number      - The event to remove a handler
 *              Address         - Address of the handler
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Remove a handler for a General Purpose acpi_event.
 *
 ******************************************************************************/
acpi_status
acpi_remove_gpe_handler(acpi_handle gpe_device,
                        u32 gpe_number, acpi_gpe_handler address)
{
        struct acpi_gpe_event_info *gpe_event_info;
        struct acpi_gpe_handler_info *handler;
        acpi_status status;
        acpi_cpu_flags flags;

        ACPI_FUNCTION_TRACE(acpi_remove_gpe_handler);

        /* Parameter validation */

        if (!address) {
                return_ACPI_STATUS(AE_BAD_PARAMETER);
        }

        /* Make sure all deferred tasks are completed */

        acpi_os_wait_events_complete(NULL);

        status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);

        /* Ensure that we have a valid GPE number */

        gpe_event_info = acpi_ev_get_gpe_event_info(gpe_device, gpe_number);
        if (!gpe_event_info) {
                status = AE_BAD_PARAMETER;
                goto unlock_and_exit;
        }

        /* Make sure that a handler is indeed installed */

        if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) !=
            ACPI_GPE_DISPATCH_HANDLER) {
                status = AE_NOT_EXIST;
                goto unlock_and_exit;
        }

        /* Make sure that the installed handler is the same */

        if (gpe_event_info->dispatch.handler->address != address) {
                status = AE_BAD_PARAMETER;
                goto unlock_and_exit;
        }

        /* Remove the handler */

        handler = gpe_event_info->dispatch.handler;

        /* Restore Method node (if any), set dispatch flags */

        gpe_event_info->dispatch.method_node = handler->method_node;
        gpe_event_info->flags &=
                ~(ACPI_GPE_XRUPT_TYPE_MASK | ACPI_GPE_DISPATCH_MASK);
        gpe_event_info->flags |= handler->original_flags;

        /*
         * If the GPE was previously associated with a method and it was
         * enabled, it should be enabled at this point to restore the
         * post-initialization configuration.
         */

        if ((handler->original_flags & ACPI_GPE_DISPATCH_METHOD)
            && handler->originally_enabled)
                (void)acpi_ev_add_gpe_reference(gpe_event_info);

        /* Now we can free the handler object */

        ACPI_FREE(handler);

unlock_and_exit:
        acpi_os_release_lock(acpi_gbl_gpe_lock, flags);

        (void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
        return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_remove_gpe_handler)

/*******************************************************************************
 *
 * FUNCTION:    acpi_acquire_global_lock
 *
 * PARAMETERS:  Timeout         - How long the caller is willing to wait
 *              Handle          - Where the handle to the lock is returned
 *                                (if acquired)
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Acquire the ACPI Global Lock
 *
 * Note: Allows callers with the same thread ID to acquire the global lock
 * multiple times. In other words, externally, the behavior of the global lock
 * is identical to an AML mutex. On the first acquire, a new handle is
 * returned. On any subsequent calls to acquire by the same thread, the same
 * handle is returned.
 *
 ******************************************************************************/
acpi_status acpi_acquire_global_lock(u16 timeout, u32 * handle)
{
        acpi_status status;

        if (!handle) {
                return (AE_BAD_PARAMETER);
        }

        /* Must lock interpreter to prevent race conditions */

        acpi_ex_enter_interpreter();

        status = acpi_ex_acquire_mutex_object(timeout,
                                              acpi_gbl_global_lock_mutex,
                                              acpi_os_get_thread_id());

        if (ACPI_SUCCESS(status)) {

                /* Return the global lock handle (updated in acpi_ev_acquire_global_lock) */

                *handle = acpi_gbl_global_lock_handle;
        }

        acpi_ex_exit_interpreter();
        return (status);
}

ACPI_EXPORT_SYMBOL(acpi_acquire_global_lock)

/*******************************************************************************
 *
 * FUNCTION:    acpi_release_global_lock
 *
 * PARAMETERS:  Handle      - Returned from acpi_acquire_global_lock
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Release the ACPI Global Lock. The handle must be valid.
 *
 ******************************************************************************/
acpi_status acpi_release_global_lock(u32 handle)
{
        acpi_status status;

        if (!handle || (handle != acpi_gbl_global_lock_handle)) {
                return (AE_NOT_ACQUIRED);
        }

        status = acpi_ex_release_mutex_object(acpi_gbl_global_lock_mutex);
        return (status);
}

ACPI_EXPORT_SYMBOL(acpi_release_global_lock)